Performance
Investigation: Testing

Performance testing not only identifies when response times are slow, but also
identifies when saturation takes place, as well as how loaded the resources
are.

Performance testing should be applied throughout the development cycle, as
well as during system operation. This strategy allows for changes that place
outside the development system or that have nothing to do with the developed
code. Not only can a different ISP affect the performance of the system, but
the underlying network drivers may change, a new database system may be installed,
etc.

The system load is also likely to change, as well as the pattern of usage made
by users; if these changes are not accounted for, then the system could start
to overload without any warning.

Performance testing, in a nutshell, warns when the system is reaching its limits
and needs to be optimised, scaled up or redeveloped.

What is involved in performance
testing?

The following performance testing methodology is used:

define the scope and objectives

analyse the current system, to discover where the resources and time
are being used

prioritise the areas for testing based on the cost of testing and
the accuracy/availability of testing tools